Issue: FFT Entity self-reported that, for a 6-hour duration, it did not operate its Automatic Generation Control (AGC) on Tie Line Frequency Bias as required. FFT Entity was mistakenly operating in Constant Frequency mode as a result of a software installation of an updated AGC resource file.
Finding: FRCC found that the issue constituted only a minimal risk to BPS reliability since the improper operational mode of the AGC did not cause any undue deviation in the system frequency (especially as the error occurred during the midnight shift). In addition, the system frequency was always being monitored by FFT Entity’s Energy Management System operators.
Issue: During a compliance audit, SPP RE determined FFT Entity violated BAL-003-0.1b R2.1 by only considering the frequency response for the most severe disturbances in establishing its fixed Frequency Bias. The Standard, in contrast, requires entities to observe and average frequency responses for several disturbances.
Finding: The issue posed only a minimal risk to BPS reliability because the Frequency Bias FFT Entity determined by only considering the most severe disturbances was equivalent to the one that would have resulted from the average of several disturbances. Because the two calculations were so similar, SPP RE determined there was minimal risk.